Hydrogen atom attachment to histidine and tryptophan containing peptides in the gas phase

2019 ◽  
Vol 21 (22) ◽  
pp. 11633-11641 ◽  
Author(s):  
Daiki Asakawa ◽  
Hidenori Takahashi ◽  
Shinichi Iwamoto ◽  
Koichi Tanaka
Keyword(s):  
Hydrogen Atom ◽  
Gas Phase ◽  
Bond Cleavage ◽  
Tryptophan Residue ◽  
Side Chains ◽  
Hydrogen Atoms ◽  
Fragment Ions ◽  
Gas Phase Fragmentation

In this study, we focus on the gas-phase fragmentation induced by the attachment of hydrogen atoms to the histidine and tryptophan residue side-chains in the peptide that provides the fragment ions due to Cα–Cβ bond cleavage.

Production and Characterization of Beams of Polystyrene Ions

1986 ◽  
Vol 39 (9) ◽  
pp. 1421 ◽  
Author(s):  
AG Craig ◽  
PJ Derrick
Keyword(s):  
Gas Phase ◽  
Bond Cleavage ◽  
Molecular Ions ◽  
Emitter Temperature ◽  
Charge Delocalization ◽  
Mass Fragment ◽  
Fragment Ions ◽  
Efficient Charge ◽  
Low Mass

The formation of gaseous polystyrene molecular ions [M]+ by means of the technique of field desorption is proposed to involve creation of a charged sample/gas interface and subsequent field evaporation of ions. The molecular ions so formed fragment spontaneously in the gas phase, provided the emitter temperature is sufficiently high. The polystyrene chains rupture near their ends rather than in their centres, which is proposed to be a consequence of efficient charge delocalization. Following collisional activation, the polystyrene chains break up to give low-mass fragment ions. The low-mass fragment ions are proposed to be the result of successive depolymerization steps, following initial direct bond cleavage within the polymer chain.

Elucidating the Fragmentation Mechanism of Protonated Lewis A Trisaccharide using MSn CID

2021 ◽  
pp. 146906672110690
Author(s):  
Volker Iwan ◽  
Jürgen Grotemeyer
Keyword(s):  
Gas Phase ◽  
Main Product ◽  
Bond Cleavage ◽  
Mass Analyzer ◽  
Blood Group Antigens ◽  
Fragmentation Mechanism ◽  
Esi Ms ◽  
Fragment Ions ◽  
Glycosidic Bond Cleavage ◽  
Lewis A

Lewis blood group antigens are a prominent example of isomeric oligosaccharides with biological activity. Understanding the fragmentation mechanism in the gas phase is essential for their identification and assignment by mass spectrometric methods such as ESI-MS. In this work, the [M + H]+ species of Lewis A trisaccharide and Lewis A trisaccharide methyl glycoside were studied by ESI-MS with FT-ICR as mass analyzer with respect to their fragmentation mechanism. The comparison between the underivatized and the methylated species has shown that the reducing end plays a key role in this mechanism. The results of this study question the existence of Z-type fragment ions after activation of the protonated species. The main product of the fragmentation are Y-type fragment ions and a combination of Y-type fragmentation and the loss of water at the reducing end instead of Z-type fragmentation. C-type fragment ions could not be detected. MS3 measurements also reveal that each fragment ion only occurs with the participation of a mobile proton and the possibility of glycosidic bond cleavage after fragmentation has already occurred at the reducing end as B2 fragment ion.

scholarly journals The kinetics of the interaction of atomic hydrogen with olefines II. Diffusion theory

1949 ◽  
Vol 196 (1047) ◽  
pp. 466-478 ◽  
Keyword(s):  
Hydrogen Atom ◽  
Gas Phase ◽  
Diffusion Theory ◽  
One Dimension ◽  
Hydrogen Atoms ◽  
Collision Efficiency ◽  
Atom Concentration ◽  
Differential Diffusion ◽  
Set Up ◽  
Kinetics Of

In this paper, a system is described in which diffusion of a hydrogen atom takes place effectively in one dimension. The exact differential diffusion equations can be set up and solved, taking into account the possibility of gas-phase removal of the hydrogen atom by a reaction such as H + C 2 H 4 = C 2 H 5 . The collision efficiency of such a reaction has been related to the fraction of hydrogen atoms which reach the oxide layer under certain well-defined conditions. The calculated distribution curves of hydrogen atom concentration throughout the reaction vessel are also given under various conditions.

scholarly journals The reaction of atomic hydrogen with hydrazine

1940 ◽  
Vol 175 (961) ◽  
pp. 164-186 ◽  
Keyword(s):  
Hydrogen Atom ◽  
Gas Phase ◽  
Atomic Hydrogen ◽  
Ammonia Molecule ◽  
Para Hydrogen ◽  
Hydrogen Atoms ◽  
Stationary Concentration ◽  
Essential Step ◽  
Photochemical Decomposition ◽  
The Subject

The reason for studying the reaction of hydrogen atoms with hydrazine is that a controversy has arisen in attempting to elucidate the mechanism of the photochemical decomposition of ammonia. It has been generally agreed that the ammonia molecule is decomposed to a hydrogen atom and an amine radical when it absorbs light around 2000° A. Presuming that the atomic hydrogen combines on the walls or in the gas phase it is possible to calculate what its stationary concentration ought to be under any given set of conditions. If, however, the stationary concentration is actually measured by using para-hydrogen as a detector, as was done by Farkas and Harteck (1934), it is found that the measured value is lower than the value calculated from the above assumptions. A number of suggestions, discussed in detail in the following paper, were made to explain this discrepancy, and among the most reasonable was that of Mund and van Tiggelen (1937) who suggested that the hydrazine known to be formed in the system removed such atoms more rapidly than would occur in the ordinary course of events. The result of their suggestion was the invention of elaborate schemes to explain the mechanism of the ammonia photolysis. As a further essential step in the ammonia problem it therefore seemed necessary to measure the efficiency of the reaction between hydrogen atoms and hydrazine. At the same time further information was also desirable about the photochemistry of hydrazine itself. This paper will therefore be concerned with this aspect of the subject. The results will then be discussed in the following paper together with a number of new experiments on ammonia in order that the mechanism of the ammonia reaction may be more fully established.

Formation of surface layer of hydrogen in pure aluminum

2019 ◽  
Vol 484 (1) ◽  
pp. 56-60
Author(s):  
D. A. Indejtsev ◽  
E. V. Osipova
Keyword(s):  
Surface Layer ◽  
Hydrogen Atom ◽  
Ab Initio ◽  
Pure Aluminum ◽  
Hydrogen Atoms ◽  
Energy Characteristics ◽  
Aluminum Crystal

Hydrogen atom behavior in pure aluminum is described by ab initio modelling. All main energy characteristics of the system consisting of hydrogen atoms in a periodic aluminum crystal are found.

2-Deoxyribose Radicals in the Gas Phase and Aqueous Solution. Transient Intermediates of Hydrogen Atom Abstraction from 2-Deoxyribofuranose

2005 ◽  
Vol 70 (11) ◽  
pp. 1769-1786 ◽  
Author(s):  
Luc A. Vannier ◽  
Chunxiang Yao ◽  
František Tureček
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Atom ◽  
Gas Phase ◽  
Computational Study ◽  
Hydrogen Atom Abstraction ◽  
Oh Radical ◽  
Free Energies ◽  
Intramolecular Hydrogen ◽  
Solvation Free Energies ◽  
Transient Intermediates

A computational study at correlated levels of theory is reported to address the structures and energetics of transient radicals produced by hydrogen atom abstraction from C-1, C-2, C-3, C-4, C-5, O-1, O-3, and O-5 positions in 2-deoxyribofuranose in the gas phase and in aqueous solution. In general, the carbon-centered radicals are found to be thermodynamically and kinetically more stable than the oxygen-centered ones. The most stable gas-phase radical, 2-deoxyribofuranos-5-yl (5), is produced by H-atom abstraction from C-5 and stabilized by an intramolecular hydrogen bond between the O-5 hydroxy group and O-1. The order of radical stabilities is altered in aqueous solution due to different solvation free energies. These prefer conformers that lack intramolecular hydrogen bonds and expose O-H bonds to the solvent. Carbon-centered deoxyribose radicals can undergo competitive dissociations by loss of H atoms, OH radical, or by ring cleavages that all require threshold dissociation or transition state energies >100 kJ mol-1. This points to largely non-specific dissociations of 2-deoxyribose radicals when produced by exothermic hydrogen atom abstraction from the saccharide molecule. Oxygen-centered 2-deoxyribose radicals show only marginal thermodynamic and kinetic stability and are expected to readily fragment upon formation.

Graph theory-based reaction pathway searches and DFT calculations for the mechanism studies of free radical-initiated peptide sequencing mass spectrometry (FRIPS MS): a model gas-phase reaction of GGR tri-peptide

2020 ◽  
Vol 22 (9) ◽  
pp. 5057-5069 ◽  
Author(s):  
Jae-ung Lee ◽  
Yeonjoon Kim ◽  
Woo Youn Kim ◽  
Han Bin Oh
Keyword(s):  
Graph Theory ◽  
Dft Calculations ◽  
Gas Phase ◽  
Density Functional ◽  
Reaction Pathway ◽  
Peptide Sequencing ◽  
Phase Reaction ◽  
Functional Theory ◽  
Fragmentation Mechanisms ◽  
Gas Phase Fragmentation

A new approach for elucidating gas-phase fragmentation mechanisms is proposed: graph theory-based reaction pathway searches (ACE-Reaction program) and density functional theory (DFT) calculations.

scholarly journals Two competitive INC-mediated reactions in the gas-phase fragmentation of protonated indolyl benzo[b]carbazoles

2016 ◽  
Vol 30 ◽  
pp. 20-23 ◽  
Author(s):  
Xiaoping Zhang ◽  
Kezhi Jiang ◽  
Jingfeng Zou ◽  
Zuguang Li ◽  
Mawrong Lee
Keyword(s):  
Gas Phase ◽  
Gas Phase Fragmentation

Gas-Phase Fragmentation of Polyoxotungstate Anions

2009 ◽  
Vol 48 (2) ◽  
pp. 598-606 ◽  
Author(s):  
Michelle T. Ma ◽  
Tom Waters ◽  
Karin Beyer ◽  
Rosemary Palamarczuk ◽  
Peter J. S. Richardt ◽  
...  
Keyword(s):  
Gas Phase ◽  
Gas Phase Fragmentation

Radiolysis of methylcyclopentane. III. Liquid phase mechanism and comparison of cycloalkanes

1968 ◽  
Vol 46 (20) ◽  
pp. 3235-3240 ◽  
Author(s):  
Gordon R. Freeman ◽  
E. Diane Stover
Keyword(s):  
Liquid Phase ◽  
Gas Phase ◽  
Bond Cleavage ◽  
Open Chain ◽  
Methyl Substitution ◽  
Product Yields ◽  
Total Ionization ◽  
Gamma Radiolysis ◽  
G Value

The initial yields of the major products of the gamma radiolysis of liquid methylcyclopentane (MCP) at 25° are: G(H2) = 4.2, G(1-methylcyclopentene plus methylenecyclopentane) = 2.7, G(3- plus 4-methyl-cyclopentene) = 1.0, G(open chain hexene) = 1.0, and G(bimethylcyclopentyl) = 0.9. The effects of scavengers on the product yields are reported and the mechanism is discussed.The liquid phase radiolytic decompositions of cyclohexane (CH), methylcyclohexane (MCH), cyclopentane (CP), and MCP are compared. The net amount of C—C bond cleavage is much greater in the five-membered than in the six-membered rings. Methyl substitution on the ring reduces G(H2) by about one unit, mainly because of the formation of a type of ion (QH+) that does not yield hydrogen when neutralized by an electron. The QH+ type ions are formed in MCH and MCP, but not in CH and CP. In all the systems, another type of ion (N+) that does not yield hydrogen when neutralized by an electron is formed with a G value of about unity. The type of ion (PH+) that does yield hydrogen when neutralized by an electron has a G value of 3.4 in CH and CP, but only 2.0 in MCP. It is concluded that G(total ionization) is in the vicinity of 4.4 in the liquid compounds, virtually the same as the gas phase values.

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